Historically, left heart catheterization has been most commonly performed by the retrograde aortic approach. The transseptal approach, which involves needle perforation of the atrial septum, was less often used due to risk of perforating the right or left atrial free walls or aorta. The traditional transseptal approach is described in De Ponti, et al., "Trans-septal catheterization for radiofrequency catheter ablation of cardiac arrhythmias", European Heart Journal (1998), Vol. 19, pages 943-50, the disclosure of which is incorporated herein by reference.
In recent years, however, use of transseptal technique has gained more widespread use with the introduction of technical modifications and products in the interventional area that have improved the safety and ease of performing the procedure, and the desire to ablate left-sided arrhythmiogenic substrates. Guiding sheaths are of particular benefit to physicians in performing left-sided ablation procedures as the sheaths provide stable means of delivering and supporting the deflectable ablation catheter on the left side. When a guiding sheath is used, direct access to the mitral annulus and the anterior and posterior walls can be attained. In addition, the long procedure times associated with the treatment of more complex arrhythmias, such as atrial fibrillation, necessitate the use of guiding sheaths to provide stability and directional control of the ablation catheter.
In some cases, a tachycardia substrate ablation site may be in a location that is difficult to reach with the curve on a standard guiding sheath and/or ablation catheter. A sheath with a more acute curve may be desirable. Performing a transseptal procedure initially with such a curve may be inadvisable, however, due to the tendency for such a sheath to redirect the transseptal needle away from the desired septal puncture site and increase the risk of the procedure. However, removal of the standard guiding sheath for replacement with a different curved sheath can result in loss of left atrial transseptal position. This could require a repeat transseptal puncture, which presents a challenge in a heparinized patient. Accordingly, a need exists for an improved transseptal left heart catheterization method.